login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A038088 Number of n-node rooted identity trees of height 4. 3
1, 3, 5, 8, 12, 17, 23, 32, 41, 52, 66, 83, 102, 124, 152, 181, 216, 255, 299, 346, 400, 458, 521, 588, 659, 735, 814, 896, 979, 1067, 1151, 1239, 1324, 1407, 1486, 1564, 1635, 1700, 1759, 1809, 1853, 1887, 1912, 1925, 1932, 1925, 1912, 1887, 1853 (list; graph; refs; listen; history; text; internal format)
OFFSET

5,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 5..97

Index entries for sequences related to rooted trees

FORMULA

a(n) = A038083(n) - A038082(n).

MAPLE

weigh:= proc(p) proc(n) local x, k; coeff(series(mul((1+x^k)^p(k), k=1..n), x, n+1), x, n) end end: wsh:= p-> n-> weigh(p)(n-1): f:= n-> `if`(n>0 and n<12, [1$3, 2$5, 1$3][n], 0): a:= wsh(f)-f: seq(a(n), n=5..97); # Alois P. Heinz, Sep 10 2008

MATHEMATICA

f[n_]:=Nest[CoefficientList[Series[Product[(1+x^i)^#[[i]], {i, 1, Length[#]}], {x, 0, 50}], x]&, {1}, n]; Drop[f[4]-PadRight[f[3], Length[f[4]]], 4] (* Geoffrey Critzer, Aug 01 2013 *)

CROSSREFS

Cf. A038081-A038093.

Column k=4 of A227819.

Sequence in context: A023544 A133263 A238531 * A018917 A167385 A265061

Adjacent sequences:  A038085 A038086 A038087 * A038089 A038090 A038091

KEYWORD

nonn,fini,full

AUTHOR

Christian G. Bower, Jan 04 1999

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 25 19:09 EST 2020. Contains 331249 sequences. (Running on oeis4.)